Vehicle State Tracking Method and Apparatus for Diagnostic Testing

ABSTRACT

A vehicle state tracker tracks the state of a vehicle during a diagnostic test sequence to eliminate redundant steps between diagnostic procedures. The vehicle state tracker maintains a list of preconditions required for each diagnostic procedure, reads a current vehicle state from a memory register and verifies the current setting of the vehicle state corresponding to a specific precondition. If the precondition is required and the current setting is not valid, the state tracker further formats a test preparation step corresponding to the precondition for display to instruct a vehicle technician to satisfy the precondition. Otherwise, if the precondition is not required and the corresponding setting is valid, the state tracker formats an instruction to reverse the corresponding vehicle condition. The state tracker additionally receives feedback indicating when a precondition has been satisfied or the corresponding vehicle condition has been reversed, and updates the vehicle state in memory.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of and is a continuation of U.S. patentapplication Ser. No. 11/452,243, filed Jun. 14, 2006, entitled “VehicleState Tracking Method and Apparatus for Diagnostic Testing,” which ishereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to diagnostic equipment. Moreparticularly, the present invention relates to tracking a vehicle stateduring a diagnostic test sequence, such as a vehicle diagnostic testsequence, for diagnostic systems.

BACKGROUND OF THE INVENTION

Diagnostic systems are used by technicians and professionals invirtually all industries to perform basic and advanced system testingfunctions. For example, in the automotive, trucking, heavy equipment andaircraft industries, diagnostic test systems provide for vehicle onboardcomputer fault or trouble code display, interactive diagnostics,multiscope and multimeter functions, and electronic service manuals. Inthe medical industry, diagnostic systems provide for monitoring bodyfunctions and diagnosis of medical conditions, as well as systemdiagnostics to detect anomalies in the medical equipment.

In many industries, diagnostic systems play an increasingly importantrole in manufacturing processes, as well as in maintenance and repairthroughout the lifetime of the equipment or product. Some diagnosticsystems are based on personal computer technology and featureuser-friendly, menu-driven diagnostic applications. These systems assisttechnicians and professionals at all levels in performing systemdiagnostics on a real-time basis.

A typical diagnostic system includes a display on which instructions fordiagnostic procedures are displayed. The system also includes a systeminterface that allows the operator to view real-time operationalfeedback and diagnostic information. Thus, the operator may view, forexample, vehicle engine speed in revolutions per minute, or batteryvoltage during start cranking; or a patient's heartbeat rate or bloodpressure. With such a system, a relatively inexperienced operator mayperform advanced diagnostic procedures and diagnose complex operationalor medical problems.

The diagnostic procedures for diagnostic systems of this sort aretypically developed by experienced technical experts or professionals.The technical expert or professional provides the technical experienceand knowledge required to develop complex diagnostic procedures. Thus,the efficacy of the diagnostic procedures, in particular the sequence inwhich the diagnostic procedures are performed, is highly dependent onthe expertise of the technical expert or professional authoring theprocedures.

Some existing diagnostic systems have a disadvantage in that eachdiagnostic procedure in a sequence of diagnostic procedures includestest preparation steps without regard to the preceding diagnostic testprocedures. As a result, when performing the diagnostic procedures, thevehicle technician may return the vehicle to a default startingconfiguration at the end of an individual diagnostic procedure, only torealize that the following test procedure requires one or more of thesame test preparation steps. This process can result in the expenditureof unnecessary time, cost and duplication of effort. Accordingly, it isdesirable to provide a method and apparatus for tracking the state of avehicle during a sequence of diagnostic test procedures in a format thatcan be executed on a PC-based diagnostic system.

SUMMARY OF THE INVENTION

The foregoing needs are met, to a great extent, by the presentinvention, wherein in one aspect an apparatus and method are providedthat in some embodiments can track the state of a vehicle during asequence of diagnostic test procedures in a format that can be executedon a PC-based diagnostic system.

In accordance with one aspect of the present invention, acomputer-implemented method of tracking a state of a vehicle during adiagnostic test sequence can include determining a precondition requiredfor a diagnostic test, reading a state register and verifying a currentfirst setting of the state register corresponding to the precondition.In addition, the method can include specifying a first test preparationstep related to the precondition based on the first setting beinginvalid.

In accordance with another aspect of the present invention, a computerprogram product for tracking a state of a vehicle during a diagnostictest sequence, including a computer-readable medium encoded withinstructions configured to be executed by a processor in order toperform predetermined operations that can include determining aprecondition required for a diagnostic test, reading a state registerand verifying a current first setting of the state registercorresponding to the precondition. In addition, the predeterminedoperations can include specifying a first test preparation step relatedto the precondition based on the first setting being invalid.

In accordance with yet another aspect of the present invention, adiagnostic tool for tracking a state of a vehicle during a diagnostictest sequence can include a precondition determiner configured todetermine a precondition required for a diagnostic test, a state readerconfigured to read a state register and a setting verifier configured toverify a state register. In addition, the diagnostic tool can include atest preparation step specifier configured to specify a first testpreparation step related to the precondition based on the first settingbeing invalid.

There has thus been outlined, rather broadly, certain embodiments of theinvention in order that the detailed description thereof herein may bebetter understood, and in order that the present contribution to the artmay be better appreciated. There are, of course, additional embodimentsof the invention that will be described below and which will form thesubject matter of the claims appended hereto.

In this respect, before explaining at least one embodiment of theinvention in detail, it is to be understood that the invention is notlimited in its application to the details of construction and to thearrangements of the components set forth in the following description orillustrated in the drawings. The invention is capable of embodiments inaddition to those described and of being practiced and carried out invarious ways. Also, it is to be understood that the phraseology andterminology employed herein, as well as the abstract, are for thepurpose of description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conceptionupon which this disclosure is based may readily be utilized as a basisfor the designing of other structures, methods and systems for carryingout the several purposes of the present invention. It is important,therefore, that the claims be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary vehicle diagnostic test setup of a typesuitable for carrying out the functions of an embodiment of theinvention.

FIG. 2 is a schematic diagram illustrating a vehicle state trackeraccording to a preferred embodiment of the invention.

FIG. 3 is a flowchart illustrating steps that may be followed to trackthe state of a vehicle in accordance with one embodiment of the methodor process.

DETAILED DESCRIPTION

An embodiment of the present invention provides a vehicle state trackerthat facilitates performance of vehicle diagnostic test sequences bytracking the state of the subject vehicle during and between individualdiagnostic test procedures. The vehicle state tracker can help toeliminate duplication of efforts during a diagnostic test sequence bykeeping track of the current vehicle test configuration and providingtest preparation steps to reconfigure the vehicle between individualdiagnostic procedures without redundant steps. The vehicle state trackercan track the current state of the vehicle by maintaining a current listof preconditions, or vehicle test configuration information.

The vehicle state tracker can include a precondition determiner that candetermine the preconditions required for a subsequent diagnosticprocedure, a state reader that can read a current state, for example,from a memory register, and a setting verifier than can verify thecurrent setting of the vehicle state with regard to an individualprecondition required for the diagnostic procedure. The vehicle statetracker can also include a test prep step formatter that can format atest preparation step related to a required precondition for display ona display device, if the precondition is required for the test procedureand the current setting of the vehicle state corresponding to theprecondition is not valid. The vehicle state tracker can further includea feedback receiver that can receive feedback from a user, the vehicleor test equipment indicating that the required precondition has beensatisfied, and a state updater that can update the vehicle state, forexample, in a memory register, to reflect the status of theprecondition.

Similarly, the vehicle state tracker can determine a vehicle conditionthat is not required for the subsequent diagnostic procedure, verify thecurrent setting of the vehicle state with regard to the condition, andformat a test preparation step that instructs the vehicle technician toreverse the condition, if the condition is not required for thesubsequent test procedure and the current setting is valid.

The terms “valid” and “invalid” as used in this disclosure regarding thevehicle state settings corresponding to preconditions describe thevehicle state setting. As used in this disclosure, the term “valid”means that the current setting indicates that the precondition is set,indicating that the precondition is currently met or the correspondingvehicle test configuration is currently set up. Correspondingly, theterms “invalid” or “not valid” as used in this disclosure mean that thecurrent vehicle state setting is not set, indicating that thecorresponding precondition is not currently met or that thecorresponding vehicle test configuration is not currently set up.

An embodiment of the vehicle state tracker can complement or can be anintegral part of a diagnostic test procedure generator. An example of adiagnostic test procedure generator that is compatible with theinteractive diagnostic schematic generator is disclosed in copendingU.S. patent application, entitled “Diagnostic Decision Sequencing Methodand Apparatus for Optimizing a Diagnostic Test Plan,” filed concurrentlyherewith by Fountain, et al., the disclosure of which is herebyincorporated by reference in its entirety.

The invention will now be described with reference to the drawingfigures, in which like reference numerals refer to like partsthroughout. FIG. 1 illustrates a vehicle test configuration that iscompatible with the present inventive method and apparatus. A vehiclestate tracker 10 can include a personal computer 12 with a displaydevice 14. The vehicle state tracker 10 can be coupled to a vehicle 16,including, for example, a vehicle onboard computer 18. For example, thevehicle state tracker 10 can be coupled to the vehicle onboard computer18 by way of a vehicle interface box 20, as shown in FIG. 1. The vehicletest configuration can further include electrical links 22, 24, such aswires, cables, data buses, a communication network or a wirelessnetwork. The vehicle state tracker 10 can display diagnostic testprocedure instructions to a vehicle technician to aid in performingvehicle diagnostics. The vehicle state tracker 10 can also receivefeedback from the vehicle 16.

As illustrated in FIG. 2, a vehicle state tracker 10 can include aprocessor 26, a memory 28, an input/output device 30, a preconditiondeterminer 32, a state reader 34, a setting verifier 36, a testpreparation step formatter 38, a feedback receiver 40, and a stateupdater 42, all of which can be interconnected by a data link 44. Theprocessor 12, the memory 14, the input/output device 16 and the displaydevice 34 can be part of a general computer, such as a personal computer(PC), a UNIX workstation, a server, a mainframe computer, a personaldigital assistant (PDA), or some combination of these. Alternatively,the processor 12, the memory 14 and the input/output device 16 can bepart of a specialized computing device, such as a vehicle diagnosticsscan tool. The remaining components can include programming code, suchas source code, object code or executable code, stored on acomputer-readable medium that can be loaded into the memory 14 andprocessed by the processor 12 in order to perform the desired functionsof the vehicle state tracker 10.

In various embodiments, the vehicle state tracker 10 can be coupled to acommunication network, which can include any viable combination ofdevices and systems capable of linking computer-based systems, such asthe Internet; an intranet or extranet; a local area network (LAN); awide area network (WAN); a direct cable connection; a private network; apublic network; an Ethernet-based system; a token ring; a value-addednetwork; a telephony-based system, including, for example, T1 or E1devices; an Asynchronous Transfer Mode (ATM) network; a wired system; awireless system; an optical system; a combination of any number ofdistributed processing networks or systems or the like.

An embodiment of the vehicle state tracker 10 can be coupled to thecommunication network by way of the local data link, which in variousembodiments can incorporate any combination of devices—as well as anyassociated software or firmware—configured to couple processor-basedsystems, such as modems, network interface cards, serial buses, parallelbuses, LAN or WAN interfaces, wireless or optical interfaces and thelike, along with any associated transmission protocols, as may bedesired or required by the design.

Additionally, an embodiment of the vehicle state tracker 10 cancommunicate information to the user and request user input by way of aninteractive, menu-driven, visual display-based user interface, orgraphical user interface (GUI). The user interface can be executed, forexample, on a personal computer (PC) with a mouse and keyboard, withwhich the user may interactively input information using directmanipulation of the GUI. Direct manipulation can include the use of apointing device, such as a mouse or a stylus, to select from a varietyof selectable fields, including selectable menus, drop-down menus, tabs,buttons, bullets, checkboxes, text boxes, and the like. Nevertheless,various embodiments of the invention may incorporate any number ofadditional functional user interface schemes in place of this interfacescheme, with or without the use of a mouse or buttons or keys, includingfor example, a trackball, a touch screen or a voice-activated system.

The precondition determiner 32 can determine a set of preconditions, orvehicle test configuration requirements, necessary for an individualdiagnostic test procedure. Preconditions and corresponding testpreparation steps can be created, or authored, for example, by an expertdiagnostics technician. Preconditions can also be formatted to bereusable in various diagnostic test procedures, which can save timeduring the authoring phase of diagnostic test procedures. In operation,the precondition determiner 32 typically can determine the preconditionsrequired for a subsequent diagnostic test procedure before thecompletion of a current diagnostic test procedure in order to prevent orminimize redundant efforts at the completion of the current diagnosticprocedure and at the initiation of the subsequent diagnostic procedure.

The state reader 34 can read a current state of the vehicle, forexample, from a memory register. In some embodiments, the vehicle statecan be stored in a processor register, while in other embodiments thevehicle state can be stored in a main memory register or in a memoryregister of a storage device associated with the personal computer 12.The setting verifier 36 can verify a current setting of the vehiclestate with regard to a specific precondition, or a group of currentsettings corresponding to a number of preconditions.

Regarding a precondition that is required for the subsequent testprocedure, if the corresponding vehicle state setting is currently notvalid, the test preparation step formatter 38 can format a testpreparation step for display on the display device 14 to instruct thevehicle technician to set up the required precondition or vehicle testconfiguration. Of course, if the precondition is required for thesubsequent test procedure and the corresponding vehicle state setting iscurrently valid, the test preparation step formatter 38 may elect not toformat a test preparation step for display.

Thus, the test preparation step can be displayed to the vehicletechnician to instruct the technician to satisfy a required preconditionfor the diagnostic procedure. Correspondingly, if the precondition wasrequired for the current diagnostic procedure and as also required forthe subsequent diagnostic procedure, the vehicle diagnostic system doesnot instruct the vehicle technician to perform redundant vehicle testconfiguration setup labor. As a result, the vehicle state tracker 10 canhelp eliminate repetitive steps, facilitating a faster and more accuratediagnosis of a vehicle operational problem.

In addition, the vehicle state tracker 10 can include a feedbackreceiver 40 that can receive feedback indicating when the preconditionhas been satisfied. For example, the feedback receiver 40 can receive adata signal from the vehicle onboard computer 18 indicating that theprecondition has been satisfied. Similarly, the feedback receiver 40 canreceive a feedback signal from test equipment, such as a digitalmultimeter, coupled to the vehicle 16. Otherwise, the feedback receiver40 can receive user input from the vehicle technician by way of theinput/output device 30 indicating that the precondition has beensatisfied, or that the vehicle technician has complied with the testpreparation step instructions.

Once the precondition has been satisfied, the state updater 42 canupdate the vehicle state, for example, in a memory register, to reflecta valid setting corresponding to the precondition. Thus, the vehiclestate can be continuously updated to maintain a current and accuratevehicle state that is available to the diagnostic system at any time inorder to determine test preparation steps required to reconfigure thevehicle 16 between diagnostic procedures in a diagnostic test sequence.

In the case that the vehicle condition is currently valid but is notrequired for a subsequent test procedure, the test preparation stepformatter 38 can format a test preparation step for display instructingthe vehicle technician to reverse, or undo, the vehicle condition.Correspondingly, the feedback receiver 40 can receive feedback asdescribed above indicating that the condition has been reversed, and thestate updater 42 can update the vehicle state, for example, in a memoryregister, to reflect an invalid setting corresponding to the condition,or precondition.

The vehicle state tracker 10 can maintain vehicle state settings for anynumber of vehicle preconditions associated with the diagnostic testprocedures. For example, preconditions can include the following:

-   -   an ignition switch position    -   an engine run condition    -   a throttle position    -   an engine speed    -   a vehicle speed    -   a test equipment connection    -   a vehicle electrical connection condition    -   an ambient air temperature    -   an engine inlet temperature    -   an engine lubricant pressure    -   an engine lubricant temperature    -   an engine lubricant level    -   an engine coolant temperature    -   an engine coolant specific gravity    -   an engine exhaust gas temperature    -   an engine exhaust gas content    -   a transmission setting    -   a brake pedal position    -   a parking brake position    -   a brake fluid pressure    -   a fuel level    -   a fuel supply pressure    -   a battery voltage    -   a battery charging system voltage    -   a battery charging system current    -   an ignition voltage    -   an ignition current    -   an engine cylinder compression    -   a vehicle configuration, or    -   a vehicle modification.

As an operational example, in preparation for performing a diagnosticprocedure on a vehicle to determine if a throttle position sensor (TPS)terminal wire is shorted to the battery positive voltage source, theprecondition determiner 32 may determine that the following fourpreconditions must be met:

-   -   ignition switch “on”    -   TPS connector disconnected    -   voltmeter (VOM) red lead connected to TPS connector socket    -   voltmeter (VOM) black lead connected to electrical ground        The state reader 34 may then read the current state of the        vehicle from a memory register, and the setting verifier 36 may        determine that the ignition switch is currently “on” (valid),        but that the remaining three preconditions are currently not        valid. As a result, the test preparation step formatter 38 can        format a graphical user interface window for display on a        display device with the following test preparation steps:    -   D Disconnect TPS    -   Connect VOM red lead to TPS connector socket    -   Connect VOM black lead to battery negative post        After completing the required test preparation steps, the        vehicle technician can provide a user input by way of the        input/output device, such as a keyboard, a mouse, or a sylus, to        indicate that the test preparation steps have been completed.        The user input can be received by the feedback receiver 40, and        in response, the state updater 42 can write the new vehicle        state including the three newly valid preconditions to the        memory register.

FIG. 3 is a flowchart illustrating a sequence of steps that can beperformed in order to track the state of a vehicle during a diagnostictest sequence. The process can begin by proceeding to step 46,“Determine Preconditions,” in which a precondition or a group ofpreconditions required for an individual diagnostic test procedure canbe determined. As described above, preconditions typically aredetermined for a subsequent test procedure, that is to follow a currentprocedure that has not yet been completed, in order to avoid repetitivesteps during the transition from the current diagnostic procedure to thesubsequent diagnostic procedure.

Then, in step 48, “Read State Register,” a vehicle state can be read,for example, from a memory register. As described above, the vehiclestate can be stored in a processor register, a main memory or aperipheral storage device. After the preconditions have been determinedand the current vehicle state has been read, in step 50, “VerifyPrecondition Setting,” the current setting of the vehicle statecorresponding to a specific precondition can be verified. For example,an individual bit in a memory register can be verified.

If the precondition is required for the subsequent diagnostic testprocedure and the current vehicle state setting corresponding to theprecondition is not valid, in step 52, “Format Test Preparation Step,” atest preparation step can be formatted for display on a display deviceinstructing the vehicle technician to satisfy the precondition, or setup the corresponding vehicle condition. Otherwise, if the preconditionis not required for the subsequent diagnostic procedure and the currentvehicle state setting corresponding to the precondition is valid, a testpreparation step can be formatted instructing the vehicle technician toreverse the vehicle condition corresponding to the precondition.

Next, in step 54, “Receive Feedback,” feedback can be receivedindicating either that the precondition has been satisfied or that thecorresponding vehicle condition has been reversed. As described above,the feedback can be received as a data signal from the vehicle onboardcomputer, a test equipment signal from test equipment coupled to thevehicle, or user input.

At this point, in step 60, “Update State Register,” the vehicle statesetting corresponding to the precondition can be updated to indicateeither that the precondition has been satisfied (valid) or that thecorresponding vehicle condition has been reversed (invalid). In thisway, the current and accurate state of the vehicle configuration andconditions can be maintained, for example, in a memory register.Tracking the current vehicle state by this process can facilitateefficient vehicle diagnostic testing by eliminating or minimizingduplicative efforts between diagnostic test steps in a diagnostic testsequence.

FIGS. 2 and 3 are block diagrams and flowcharts of methods, apparatusesand computer program products according to various embodiments of thepresent invention. It will be understood that each block or step of theblock diagram, flowchart and control flow illustrations, andcombinations of blocks in the block diagram, flowchart and control flowillustrations, can be implemented by computer program instructions orother means. Although computer program instructions are discussed, anapparatus according to the present invention can include other means,such as hardware or some combination of hardware and software, includingone or more processors or controllers, for performing the disclosedfunctions.

In this regard, FIG. 2 depicts the apparatus of one embodiment includingseveral of the key components of a general purpose computer by which anembodiment of the present invention may be implemented. Those ofordinary skill in the art will appreciate that a computer can includemany more components than those shown in FIG. 2. However, it is notnecessary that all of these generally conventional components be shownin order to disclose an illustrative embodiment for practicing theinvention. The general purpose computer can include a processing unit 26and a system memory 28, which may include random access memory (RAM) andread-only memory (ROM). The computer also may include nonvolatilestorage memory, such as a hard disk drive, where additional data can bestored.

An embodiment of the present invention can also include one or moreinput or output devices 30, such as a mouse, keyboard, monitor, and thelike. A display can be provided for viewing text and graphical data, aswell as a user interface to allow a user to request specific operations.Furthermore, an embodiment of the present invention may be connected toone or more remote computers via a network interface. The connection maybe over a local area network (LAN), wide area network (WAN), theInternet, or the like, and can include all of the necessary circuitryfor such a connection.

Typically, computer program instructions may be loaded onto the computeror other general purpose programmable machine to produce a specializedmachine, such that the instructions that execute on the computer orother programmable machine create means for implementing the functionsspecified in the block diagrams, schematic diagrams or flowcharts. Suchcomputer program instructions may also be stored in a computer-readablemedium that when loaded into a computer or other programmable machinecan direct the machine to function in a particular manner, such that theinstructions stored in the computer-readable medium produce an articleof manufacture including instruction means that implement the functionspecified in the block diagrams, schematic diagrams or flowcharts.

In addition, the computer program instructions may be loaded into acomputer or other programmable machine to cause a series of operationalsteps to be performed by the computer or other programmable machine toproduce a computer-implemented process, such that the instructions thatexecute on the computer or other programmable machine provide steps forimplementing the functions specified in the block diagram, schematicdiagram, flowchart block or step.

Accordingly, blocks or steps of the block diagram, flowchart or controlflow illustrations support combinations of means for performing thespecified functions, combinations of steps for performing the specifiedfunctions and program instruction means for performing the specifiedfunctions. It will also be understood that each block or step of theblock diagrams, schematic diagrams or flowcharts, as well ascombinations of blocks or steps, can be implemented by special purposehardware-based computer systems, or combinations of special purposehardware and computer instructions, that perform the specified functionsor steps.

As an example, provided for purposes of illustration only, a data inputsoftware tool of a search engine application can be a representativemeans for receiving a query including one or more search terms. Similarsoftware tools of applications, or implementations of embodiments of thepresent invention, can be means for performing the specified functions.For example, an embodiment of the present invention may include computersoftware for interfacing a processing element with a user-controlledinput device, such as a mouse, keyboard, touch screen display, scanner,or the like. Similarly, an output of an embodiment of the presentinvention may include, for example, a combination of display software,video card hardware, and display hardware. A processing element mayinclude, for example, a controller or microprocessor, such as a centralprocessing unit (CPU), arithmetic logic unit (ALU), or control unit.

The many features and advantages of the invention are apparent from thedetailed specification, and thus, it is intended by the appended claimsto cover all such features and advantages of the invention which fallwithin the true spirit and scope of the invention. Further, sincenumerous modifications and variations will readily occur to thoseskilled in the art, it is not desired to limit the invention to theexact construction and operation illustrated and described, andaccordingly, all suitable modifications and equivalents may be resortedto, falling within the scope of the invention.

1. A diagnostic tool for use with a diagnostic test sequence,comprising: a precondition determiner configured to determine aplurality of preconditions required for a subsequent diagnostic test anddetermine if any currently valid preconditions in a current diagnostictest is needed for the subsequent diagnostic test; a setting verifierconfigured to verify a state of each of the plurality of preconditionsand the currently valid preconditions; and a preparatory step formatterconfigured to provide a test step for each of the plurality ofconditions that is in an invalid state.
 2. The diagnostic tool of claim1 further comprising: a state reader configured to read a state of avehicle.
 3. The diagnostic tool of claim 1 further comprising: an updatestate register configured to update a register on whether the pluralityof preconditions are now valid or if the currently valid preconditionsare now invalid.
 4. The diagnostic tool of claim 1 further comprising: afeedback receiver configured to receive a feedback that the plurality ofpreconditions have been satisfied.
 5. The diagnostic tool of claim 4,wherein the feedback is from a vehicle onboard computer data, a testequipment data or a user input.
 6. The diagnostic tool of claim 1,wherein the state of the plurality of preconditions can be stored in aregister of a memory of the diagnostic tool.
 7. The diagnostic tool ofclaim 1, wherein if the precondition determiner determines that any ofthe currently valid preconditions in the current diagnostic test is notneeded for the subsequent diagnostic test, then the step preparatorystep formatter provides a reverse step to a user to reverse the notneeded currently valid precondition.
 8. The diagnostic tool of claim 7further comprising: a feedback receiver configured to receive feedbackthat the not needed currently valid precondition has been reversed.
 9. Acomputer implemented method of tracking a state of preconditions,comprising the steps of: determining the precondition required for asubsequent diagnostic test; determining if any currently validpreconditions in a current diagnostic test is needed for the subsequentdiagnostic test; providing instructions to a user to make theprecondition required for the subsequent diagnostic test valid if theprecondition is not valid; and providing instructions to the user tomake any of the currently valid preconditions invalid if the currentlyvalid preconditions is not required by the subsequent diagnostic test.10. The computer implemented method of claim 9 further comprising thestep of: verifying that the user made all of the preconditions requiredfor the subsequent diagnostic test valid.
 11. The computer implementedmethod of claim 9 further comprising the step of: verifying that theuser made all of the currently valid preconditions not required for thesubsequent diagnostic invalid.
 12. The computer implemented method ofclaim 10 further comprising the step of: updating a state register toreflect that the preconditions required for the subsequent diagnostictest are valid.
 13. The computer implemented method of claim 11 furthercomprising the step of: updating a state register to reflect that thecurrently valid preconditions not required for the subsequent diagnostictest are invalid.
 14. The computer implemented method of claim 10,wherein the verification based on a vehicle onboard computer data, atest equipment date or a user input.
 15. The computer implemented methodof claim 11, wherein the verification based on a vehicle onboardcomputer data, a test equipment date or a user input.
 16. A diagnostictool for use with a diagnostic test sequence, comprising: a preconditiondeterminer means configured to determine a plurality of preconditionsrequired for a subsequent diagnostic test and determine if any currentlyvalid preconditions in a current diagnostic test is needed for thesubsequent diagnostic test; a setting verifier means configured toverify a state of each of the plurality of preconditions and thecurrently valid preconditions; and a preparatory step formatter meansconfigured to provide a test step for each of the plurality ofconditions that is in an invalid state.
 17. The diagnostic tool of claim16 further comprising: a state reader means configured to read a stateof a vehicle.
 18. The diagnostic tool of claim 16 further comprising: anupdate state register means configured to update a register on whetherthe plurality of preconditions are now valid or if the currently validpreconditions are now invalid.
 19. The diagnostic tool of claim 16further comprising: a feedback receiver means configured to receive afeedback that the plurality of preconditions have been satisfied. 20.The diagnostic tool of claim 19, wherein the feedback is from a vehicleonboard computer data, a test equipment data or a user input.
 21. Thediagnostic tool of claim 16, wherein the state of the plurality ofpreconditions can be stored in a register of a memory of the diagnostictool.
 22. The diagnostic tool of claim 16, wherein if the preconditiondeterminer means determines that any of the currently validpreconditions in the current diagnostic test is not needed for thesubsequent diagnostic test, then the step preparatory step formatterprovides a reverse step to a user to reverse the not needed currentlyvalid precondition.
 23. The diagnostic tool of claim 22 furthercomprising: a feedback receiver means configured to receive feedbackthat the not needed currently valid precondition has been reversed.